Several petrochemical industry pump shaft seal introduction
Petrochemical industry pump shaft seal is roughly divided into contact sealing, non-contact seal two kinds. Contact seal includes packing seal and mechanical seal, Non-contact sealing has labyrinth seal, spiral sealing and vice impeller sealing etc. 80～90% chemical pumps in petrochemical industry adopt mechanical seal. Mechanical seal is effective way to solve run, emit, drop, leakage, improve environmental protection and working efficiency, reduce the producting cost, it is one of the indispensable means to realize industrial modernization.
research drip
ZW600-80 type forced circulation pump, flow is 2650m3 / h, pump conveying slurry containing 8% and 10% (wt) even higher salt crystals, conveying fluid temperature over 120 ℃. The shaft seal structure includes bushings installed on the rotating axial of axial pump, front blocks, sealing rings, pump cover, back block, water block and the mechanical sealing that installed between them before and behind in series and independent of each other, mechanical sealing 1 adopts balanced type external static sealing ring compensating mechanical sealing, mechanical sealing 2 adopts double end shifting forks type mechanical sealing.
Slurry pump is Roots pump, pulp media density is l350m3 / kg, outlet pressure is 600kPa, motor speed is 1500r/min. Slurry seal uses mechanical seal form: Adopting EG flushing, using skeleton oil seal, to prevent flushing liquor leakage. Improved measures including: change push ring ends o-shape sealing ring seal position, using viton o-shape sealing ring, using PTEF materials to produce a similar skeleton oil seal, installed between fixed o-ring seats and pump body, prevent slurry into dynamic and static sealing ring, etc.
93A type reactor cooling pump (RCP) shaft seal system includes three sealing. The first seal (rank 1) is to control the leakage of the film-riding end sealing, using contactless control leakage, in long cycle operation (about 1 years), characteristics error is small. 1 sealing function is reducing the coolant pressure from 15MPa to 0.3 MPa, including spin lateral sealing and static lateral sealing ring.
American JosephL Foszcz reviewed shaft sealing, said mechanical seal can handle a variety of fluids, pressures up to 13.8MPa, rotating speed up to 50000rpm, temperatures from -254 to 649 ℃, is more and more popular in not allowed leakage pump application. This paper gives a typical mechanical seal components, including 1 stage seal, a stage seal ring, static seal ring, O-rings (2 level seals) and so on.
Part of patent description
Chinese practical new-type patent ZL99236406 reveals combined sealed-type leak-off pump includes rotating spindle, impeller and pump cover, machine block, etc, between spoken spinning spindle, impeller, pump cover and machine block to set parallel suit two sets of mechanical seal, its outer sealing is close to pump cover single end balanced static sealing ring compensating mechanical sealing (level 1 seal), the inner sealing is close to rotating spindle double end mechanical sealing (level 2 seal), the pump through combined mechanical sealing installed in pump body, make the transfer medium and isolating liquid medium separation, can avoid conveying liquid media through rotating axis face to leak outside.
Japanese NIPPONPILLARPACKINGCO.,LTD applied United States patent US5501470 reveals a non-contact shaft seal used in rotating machinery, in the shaft seal face high pressure side produced fluid membrane sealing. On rotating sealing face appearing radial or peripheral direction lined with multiple pressure grooves, produced dynamic pressure inside liquid diaphragm.
Japanese mitsubishi heavy industries applied patent JP8219297 reveals shaft sealing is applicable to high pressure rotating machine, high-pressure chamber and low-pressure chamber to seal each other, rotating ring has multi-grooves, so as to put liquid ringlike groove liquid conveyed along the outside direction as the rotating axis rotation.
Japanese NIPPONPILLARPACKINGCO., LTD applied Japanese patent JP2003185030 reveal shaft sealing adopting two line mechanical sealing, used for high pressure equipment. Its first mechanical sealing through double stage sealing parts to make second bushings can along the axial relative motion inserting internal rotating sealing ring, so first static lateral holder can maintain first static sealing ring insert in the first internal bushings. This structure can reduce the bulk and weight.
